I have a bigger suggestion to make.
Currently, if you change the way [quote] is replaced in pre_reg.tmpl , this will screw up all old posts, when you try to edit or quote them.

I assume that data is kept as HTML in the database for performance reasons, however it would greatly increase the future-proof-ness of the forum software, if it was kept additionally with the [tags] preserved in another table.

This way each action would affect both these tables and the admin could use a "re-evaluate posts" function to update the posts to the most recent theme.